Hi!

Is the odometer on your car mechanical or does it have a digital
display?

For a mechanical (analog) odometer, you would probably find a simple
burned out light bulb. Some GM vehicles have sockets for these, others
use a kind of bulb that twists in to contact points on a sort of
printed "circuit board" like material. You might also find a soldered
"grain of sand" light bulb in place.

If it has a digital display, the instrument panel may need to be
"reconditioned"...but you probably won't have to pay any $615 to do
it. If you know how to get it out of the car and have some experience
repairing electronics, you could go around and check for bad solder,
loose connectors or even missing/low voltages. Most of these displays
are of the vacuum fluorescent type, but it doesn't sound like yours is
since you can read it with a flashlight. Once you have the panel out,
you may find that the display is lit with something like a "grain of
sand" bulb or similar.

There are companies on the 'net who repair all digital instrument
panels. While yours doesn't sound like it is all digital, they might
have an idea as to what is wrong.

William